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					    Introduction to Pharmacology



Stephanie Lowry RN MSN CEN
  Associate Professor Nursing
 Riverside Community College
                 Nursing Process

 Nurses use
     Core drug knowledge
     Core patient variables
 All nurses are responsible for
     Educating
     Managing
     Monitoring the proper use of drugs

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                Assessment - Core Drug
                      Knowledge
 Pharmacotherapeutics
      Therapeutic effect of the drug
 Pharmacokinetics
      Changes that occur to the drug while in the body
 Pharmacodynamics
      Effects of the drug on the body
 Contraindications / precautions
      Conditions in which drug should not be used
 Adverse Effects
      Unintended / undesirable effects
 Drug Interactions
      Effects that occur when drug is given with another
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              Core Patient Variables
 Health Status
      Presence of disease, illness and allergy
 Life span & Gender
      Age, physiologic development, reproductive stage
 Lifestyle, Diet, and Habits
      Amount of activity, health practices
 Environment
      Where is drug administration occurring
 Culture / inherited traits
      Conditions affecting patient’s receptiveness to drug
       therapy
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           Nursing Responsibilites

 72% adults over 65 years old have 1 Rx
 40% adults over 65 have 3+ each month
 Prototype Drugs
     Group of drugs within a drug class
     Provides general info about drugs in that class




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                         Planning

 Maximize Therapeutic Effects
     Administer drugs to promote absorption
     Administer at appropriate time
     Monitor laboratory values
 Minimize Adverse Effects
     Verify allergies
     Use standard safety protocols
     Discontinue or withhold drugs as needed
     Report adverse effects

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                       Intervention

 Drug administration
 Patient / family education
     Goal of education is safe self medication
     Chronotherapy
         Correlate peak of drug activity with body’s needs
     Food, Alcohol, Cigarettes
     Laboratory effects

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                  Evaluation

 Was the outcome or goal achieved?
 Identification of reasons behind treatment
  failure




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          Historical Perspective of Drug
                  Development
 Early civilization
      Drive away evil spirits
      Invoke religious & mystical powers
 19th century
      Pharmaceutical chemistry developed
      Systematic reasoning & rigorous testing of theories
 20th century
      Computer & biotechnology technology
      Decreased animal studies
 21st century
      Develop new drugs through chemical synthesis
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        4 Sources of Drug Products

 Plants
 Animals
 Synthetic Chemicals
     Most drugs are either partial or wholly synthetic
 Genetically Engineered Chemicals
     DNA technology


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              Drug Nomenclature

 Chemical Name
     Describes drug’s atomic & molecular structure
 Generic Name
     Identifies drug’s active ingredient
     First letter of name is not capitalized
     Prefix or suffix may indicate class of drug
     Often the drugs “official” name

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              Drug Nomenclature

 Trade Name
     Brand name given by manufacturer
     Protected by trademark – use restricted to drug’s
      manufacturer.
     17 year patent on the drug
     1st letter capitalized



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             Dispensing Medications
                Generic vs Trade
 Some states regulate substitutions
 Is there a difference?
      Inert ingredients may or may not affect efficacy
 Bioavailability
      Physiologic ability of the drug to reach target cells
      May be affected by inert ingredients
 Negative Formulary Lists
      Critical meds with variable bioavailability & cannot be
       substituted

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             Drug Classifications

 Chemical Composition
     Ex: Morphine – chemical base of opium
 Physiologic effect
     Ex: Morphine - CNS depressant
 Therapeutic uses or action
     Ex: Morphine – Opiod narcotic analgesic


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        Therapeutic Drug Classes

 Anti-infammatory                 Antihypertensives
  drugs                            Antiemetics
 Drugs that lower                 Anti-diarrheal drugs
  cholesterol                      Antacids
 Anti-pyschotic drugs             antibiotics
 Anti-anxiety drugs
 Anti-depressants


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     Therapeutic Classification
     Focus –
     Cardiac care / Drugs affecting cardiovascular function

    Usefulness:                         Classification:
   Influencing blood clotting           Anticoagulants
   Lowering blood cholesterol           Antihyperlipidemics
   Lowering blood pressure              Antihypertensives
   Treating abnormal rhythm             Antidysrythmics
   Treating chest pain                  Antianginal drugs




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Pharmacologic Classification
Focus –How a therapy may be applied
             – How is high blood pressure managed?
Mechanism of Action                Pharmacological Classification
 Lowering plasma volume            Diuretics
 Blocking heart calcium            Calcium channel blockers
  channels
                                    Angiotensin converting
 Blocking hormonal activity         enzyme inhibitors (ACE)
 Blocking stress related           Sympatholytics
  activity
                                    vasodilators
 Dilating peripheral blood
  vessels


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      Drug Regulations & Standards

 Pharmacopoeia
 Food Drug & Cosmetic Act (1938)
     Prevented the sale of drugs not thoroughly tested
 Food & Drug Administration (1988)
     Controls Rx & OTC drugs
     Must approve drugs before marketing
     Herbal & dietary supplements are exempt

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        FDA Drug Approval Process
 Four phases
      Preclinical investigation
      Clinical investigation
      New Drug Application (NDA) review
      Postmarketing surveillance
 MedWatch - voluntary feedback regarding drugs
 Only 10% of drugs that begin clinical trial process
  win approval
 Average 12 years
 Approx cost to market new drug $350 million
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             Streamlining the Drug
               Approval Process
 Orphan Drugs
     Limited use drugs
     Cost to manufacture will never be recouped
     Tax breaks given to companies
 Compassionate Use
     Drugs made available with complete FDA approval
     “Investigational” drugs
 Expedited Process
     Drugs in phase 2 or 3 trials may apply for FDA approval
      in certain patient populations (AIDS)

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               Legislation Regarding
               Controlled Substances
 Harrison Narcotic Law of 1914
     legally defined the term “narcotic”
     1st effective regulation regarding manufacture of drugs
      known for their abuse potential
 1970 Comprehensive Drug Abuse Prevention and
  Control Act
     Established the Drug Enforcement Agency (DEA)
     Categorized & controlled drugs according to abuse
      potential & medical usefulness on a scale of 1-5


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       Pharmacology & Regulations

 Nurses regulated by 3 authorities
      Federal – conditions of med administration
      State – who may prescribe, dispense & administer
       medications
      Hospital / Agency – policies regarding med
       administration & reporting process
 Controlled Substances
      Most Heavily regulated
      Highest potential for abuse


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             Classification of Drugs

 Desirable (therapeutic) / Undesirable (adverse)
 Prescription Medications
     Opportunity to examine & determine diagnosis
     Maximize therapy
     Control amount & frequency of med dispensed
     Educate patient regarding medication & diagnosis



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      Classification of Drugs (cont)

 Nonprescription / Over the Counter (OTC)
     Readily available, no appointment necessary
     Less costly
     Challenging to decide which medication is best
     Possible interactions with other meds & foods
     More potential for abuse / misuse due to
      ignorance regarding medical terminology


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Categories of Safety in
     Pregnancy




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              Counterfeit Drugs

 WHO estimates 10% meds sold globally are
  counterfeit
 Lives lost not from toxic substances but lack of
  “real” medication
 $35 Billion in black market profits
 “Uplabeling” – passing off 10mg dose of a drug as
  40mg instead
 AIDS & ER drugs most likely to be counterfeited

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       Does advertising Pay Off?

 $791 million in 1996
 $1.8 billion in 1999
 $ 2.5 billion in 2000
 Advertising makes consumers demand more
  expensive, newer drugs when older / cheaper
  drugs may be just as effective


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     What about us as consumers?


 What are the marketing strategies?
 How do they educate non healthcare
  professionals?
 Is pushing medications an an ethical issues?




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          What should you do……
             Does IV = PO?
 MD order reads:
     Lasix 80mg IV STAT for a patient who is SOB
      with pulmonary edema
     Only PO form is available so nurse says “give it,
      Lasix is Lasix & he needs the med”




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       Drug Action – Three Phases
 First phase:
    Pharmaceutic (dissolution)

       Becomes a solution so it can cross the biologic
        membrane
       This phase is skipped when meds are given
        parenterally




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                    What’s In a Drug?
 Excipients –
      fillers or inert substances that allow the drug to take on a
       size or shape that will enhance is dissolution
      Increase the absorbability of the drug
          (Penicillin with Potassium)
 Rate limiting –
      Time it takes the drug to disintegrate & dissolve to
       become available for the body to absorb
      Occurs faster in acidic fluids pH of 1 or 2
      Geriatrics & pediatrics have less gastric acidity – drug
       absorption is slower


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            Pharmacotherapeutics

 Establish an expected outcome or end point
  of therapy
 What is the purpose of the medication?
     Curing a disease, reducing symptoms, slowing
      disease process, preventing disease
 Several types of therapy:
     Acute, Maintenance, Supplemental, Palliative,
      Supportive, Prophylactic / Empiric
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               Acute Therapy

 Intensive drug treatment – used most in
  critically ill patients
 Used to sustain life or treat disease
 Examples?




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          Maintenance Therapy

 Does not eradicate problems but does prevent
  progression of a disease or condition
 Used for chronic illness
 Examples?




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         Supplemental Therapy

 Provides the body with a substance needed to
  maintain normal function
 Can’t be made by the body or inadequate
  supply available
 Examples?



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             Palliative Therapy

 Provide comfort to the patient
 Used in the end stages of an illness when all
  curative therapy has failed
 Examples?




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            Supportive Therapy

 Maintains the integrity of body functions
  while the patient is recovering from illness or
  trauma
 Examples?




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   Prophylactic / Empiric Therapy

 Prevents illness
 Prophylactic – science based
 Empiric – experience based
 Examples?




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       Pharmacokinetic –                   2 nd   Phase

 The process of drug movement to achieve
  drug action
 Four processes
     Absorption
     Distribution
     Metabolism
     Excretion

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             Absorption –                  1 st   process

 Movement of drug particles from GI tract
  occurs by
     Passive Absorption
         Diffusion across a membrane
     Active Absorption
       Requires a carrier such as an enzyme or protein
       GI membrane composed mostly of lipids & protein,
        drugs pass easily
     Pinocytosis
         Cells carry the drug by engulfing the drug particles
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                The Affect of Food

 May interfere with dissolution & absorption of
  certain drugs
      Larger doses of a medication may be necessary to
       compensate for drug loss (Pen G)
 Can enhance absorption of other drugs
      Some drugs require a more acidic environment & food
       stimulates gastric acid secretion
 Drugs may cause gastric irritation & food acts as a
  protectant

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               Enteral Route

 Absorbed through mucosa of stomach or
  small intestine into mesenteric blood system
  then through portal vein to the liver
 Hepatic enzyme systems metabolize it &
  pass remaining drug into systemic circulation




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               1 st   Pass Effect

 Decreases the availability of some
  medications
 Some drugs are not given orally due to this
  process (Lidocaine, Nitroglycerins)
 Dose of Inderal given IV is 1mg vs 40mg
  when given po



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           What affects Absorption?

 Acid changes in stomach
      Time of day, age of patient , food, other medications
 Decreased gastric emptying
      Pain, stress, solid foods, exercise
 Circulatory Issues
      IM injections absorbed faster in deltoid than gluteus




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                     Bioavailability

 Percentage of the administered drug dose that
  reaches the systemic circulation
 Oral route always < 100%
 IV route always 100%
 Factors altering bioavailability
      Drug Form (tablet, capsule etc)
      Route
      GI mucosa
      Food or other drugs
      Changes in liver function
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                Drug Interactions

 Additive effect
     Combined effect of the drugs is improved
 Antagonistic effect
     One drug interferes with the action of another
 Displacement
     One drug replaces another at the receptor site
      increasing the effect of the first drug

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       Distribution –              2 nd   process

 Process by which the drug becomes available
  to body fluids & body tissues




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           Metabolism or
   Biotransformation – 3rd process
 Metabolism occurs mainly in the liver
 Liver disease can alter metabolism causing
  excess drug accumulation leading to toxicity




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                How long does it last?

 Half life
      Time it takes for one half of the drug concentration to be
       eliminated
          650mg ASA at 9am (½ life is 3hours), at 12pm 162mg remains &
           at 3pm 81mg remains etc
      Diseases in liver & kidney can cause accumulation of
       drug concentrations
      Short ½ life = 4-8hrs
      Long ½ life is 24hrs
          Digoxin ½ life is 36hrs

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  Excretion or Elimination – 4th phase
 Main route of elimination is through the kidneys
      Kidney disease can influence excretion
 Elimination is influenced by urine pH, may cause
  some drugs to be eliminated faster than others
        Normal pH is 4.5-8
 Other routes of excretion are:
      Respiratory system
      Glands
      Breasts
      Bile
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         Pharmacodynamic Phase

 The effect of the drug on the body
 Drugs can cause a primary or secondary
  physiologic effect or both
 Primary effect is desirable & Secondary
  effect may be undesirable
     Examples?



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        Dose Response & Maximal
                Efficacy
 Relationship between the minimal versus the
  maximal amount of drug dose needed to
  produce a desired drug response
 All drugs have maximum drug effect
     Morphine & Darvon = both pain meds have
      different maximum efficacy



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        What are we looking for?

 Onset of Action – time it takes to reach the
  minimum effective concentration after
  administration
 Peak action – time when the drug reaches its
  highest blood or plasma concentration
 Duration of action – length of time the drug has a
  pharmacologic effect
 Some drugs produce effects in minutes, others take
  hours or days

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                        Monitoring

 Therapeutic Index estimates the margin of safety
  between what is the effective dose & lethal dose for
  a drug
      Low therapeutic Index – narrow margin of safety
       requires closer monitoring of drug levels & dosage
      High therapeutic Index – less danger of toxic effects
 Patient condition


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                 Monitoring

 Patient’s condition

 Tolerance & Dependence




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          Categories of Drug Action

 Stimulation or depression
      Cell activity or secretion from a gland increases or
       functions of a specific organ decreases
 Replacement
      Replace essential body compounds
 Inhibition or killing of organisms
      Interfere with bacterial cell growth
 Irritation
      Causes desired action in response to irritation

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       Length of Drug Action is
     dependent upon ½ life of drug
Assists with scheduling proper dosing of medications
        Short ½ life drugs are given several times a day
        Longer ½ life drugs require once a day dosing




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                Loading Dose

 Immediate drug response is desired
 Large initial dose is given to achieve a rapid
  minimum effective concentration in the
  plasma




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            Side Effects, Adverse
           Reactions &Toxic Effects
 Physiologic effects not related to desired drug
  effects
      Sometimes expected as part of drug therapy
      Not a reason to discontinue therapy
 Adverse reactions are more severe than side effects
      Always undesirable & represent variance from planned
       therapy
 Toxic effects
      Identified by monitoring plasma levels
      Occur from overdosing or drug accumulation
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         What is Tachyphylaxis ??

 Drug tolerance to a frequently repeated
  administration of a certain drug
     Narcotics
     Barbiturates
     Laxatives
     Psychotropic agents



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          The Nursing Process in
         Medication Administration
 Assess
     Drug history – diagnosed diseases, current meds,
      problems with medications
 Plan
     Therapeutic goal for medication
 Implement
     Accurate administration of medication
 Evaluate
     Response to medication (therapeutic & adverse)


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           Drug Administration
          Nursing Responsibilities
 Six Rights
     Right Med, Right Patient, Right Dose, Right
      Time, Right Route & Right Documentation
 Three Checks of Drug Administration
     Check the drug with MAR
     Check the drug when preparing, pouring or
      connecting to the IV
     Check the drug before administering it to the
      patient
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               Drug Administration
               Patient Participation
 Right to refuse medications
 Factors affecting compliance:
      Cost of medication
      Forgotten doses (scheduled for multiple times / day)
      Side effects (may discontinue if side effects are annoying)
      Self adjustment of doses ( 1 is good, 2 is better)
      No benefit noted (prolonged therapeutic effect)
      Fear of dependency (take less than prescribed)
      Unwilling to admit noncompliance ( fear of reprimand)

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          Which route is Best?

 Mode of Drug administration affects both the
  speed at which onset of action occurs & the
  magnitude of the therapeutic response
 Route may need to be altered to assist in
  absorption (po-rectal when vomiting)




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      Drug Absorption is affected by
         route of administration
 What are the:
     Advantages
     Disadvantages
     Nursing Considerations
 For the following routes of medication?
     IV, IM/Subcut, Oral, Sublingual, Rectal,
      Topical, Transdermal

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              Enteral Route

 Most common, safest, economical,
  convenient
 Most unreliable & slowest




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                   Oral Drug Forms
 Sustained Release
      Steady controlled release
      Total dose of drug may be higher
 Sublingual Tablets
      Dissolve rapidly in vascular bed
 Troches
      Used to achieve “local” affect
 Capsules
      Easier to swallow, hide “foul taste”


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               Oral Drug Forms (cont)

 Syrups
      Concentrated solution of sugar
      Resistant to mold, yeasts & microorganisms
 Elixirs
      Clear mixture that is sweetened
      Alcohol content can exceed 25%
 Emulsions & Suspensions
      2 liquids that do not mix well
      Shake & administer immediately after pouring & measuring

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              Enteric Coating

 Resist disintegration in the stomach
 Wait for alkaline environment of the small
  intestine
 Effect may be delayed in onset
 Crushing alters place & time of absorption of
  the drug – Do Not Crush


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          Enteral Drug Assessment

 Patient’s condition
     Can they tolerate an oral drug?
     Alternate routes?
 Age
     Syrups vs Elixirs
 Environment
     Easily self administered

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            Transdermal Patches

 Absorbed through the skin giving a systemic effect
 More consistent blood levels obtained
 Matrix patch
      Drug spread over entire surface of the patch
 Reservoir patch
      Drug is pooled & released via a semipermeable
       membrane
      Do not cut as too much drug may be released
      Peel back the protective layer halfway to adjust dosing

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              Parenteral Route

 Route of administration other than the GI
  tract
 Bypasses the first pass effect of the liver
 Avoids absorption issues r/t GI tract




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                  Parenteral Routes

 Intramuscular (IM)
      Faster absorption than oral route
      Requires knowledge of anatomy
 Subcutaneous (SC)
      Low volume < 2ml
 Intravenous (IV)
      Most dangerous route
      Immediate onset of action

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               Topical Route

 More uniform amount of drug delivered over
  time
 Slower onset & more prolonged duration
 Rectal route has mixed first pass & non first
  pass absorption / metabolism



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      Types of Medication Orders

1. Standing order               A. Lidocaine 50mg IV
                                  now
2. Emergency or Stat            B. Decadron 10mg po
   order                          TID
                                C. Ancef 1 gm IVPB on
3. One time order                 call to OR
                                D. Tylenol 650mg po
4. Prn order                      q4hrs prn T > 101

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    Management of Drug Therapy

 Nurses have significant role in management
  of drug therapy & are accountable for safe
  administration of medications
 Utilize the nursing process in aspects of care
 Function as a patient advocate
 Recognize limitations of knowledge & seek
  clarification when unsure

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                   Next …

 Med Errors…..how do they happen & what
  can we do?




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